Scaffold.



G. ALLEN.

SGAFPOLD. APPLICATION FILED FEB. 21, 1913.

Patented Dec. 1, 1914.

2 SHEBTSSHEET l lA/l/EN 70 WITNESSEb THE NORRIS PETER-5 CO. PHOTO-LITHQ, WASHINGTON. D. c.

G. ALLEN.

SGAFFOLD.

APPLICATION FILED FEB. 21, 1913.

' 1,119,742. Patented Dec. 1,1914.

2 SHEETS-SHEET 2.

WIT/V5565? g //Vl E/VTOR.

Wm 7 f "HE NORRIS PETERS ca, PHOTO-LITHCL, WASHINGTON. D. L

UNITED STATIEi enonennrlnnn, or 'rononro, ONTARIO, CANADA.

SCAFFOLD.

Specification of Letters Patent. I

Patented Dec. 1, 1914.

Application filed February 27, 1913. Serial No. 751,142.

1/ all whom it may concern Be it known that I, Gnonen ALLEN, of the city of Toronto, in the county of York and Provinceof Ontario, Dominion of Canada, have invented certain new and useful Improvements in Scafl olds; and I hereby declare that the following is a full, clear, and exact description of the same.

My invention relates to a scaffold in whic the platform is suspended by ropes wound on drums provided with looking devices whereby the platform can be moved to any desired elevation and securely locked in its adjusted position until the locking mechanism has been released.

For an understanding of my invention, reference is to be had to the following description and to the accompanying drawings, in which Figure 1, is a perspective view of the scaffold; Fig. 2, is a vertical section on the line aa Fig. 1; Fig. 3, is a broken front elevation of the winding mechanism; and, Fig. 4, is an end elevation of the construction shown in Fig. 3.

Like characters of reference refer to like parts throughout the specification and drawings.

In the construction of the scaffold, I use two trestle frames at, a, each of which is provided with guide bars I), 5, having guide ways 0 to receive the ends of the suspension bar d, from which hangs the platform support 6. Connected to the suspension bar (Z is one end of a suspension rope f, the other end of said rope being fastened to a winding drum 9 journaled in suitable bearings h fastened to the trestle top 2'.

The winding drum 9 is provided with a locking member j having two detents j which engage with a spring-pressed locking bar is to normally prevent the unwinding revolution of the drum 9. The winding drum and locking member j may be of a unitary character, or the locking member, as shown in Fig. 3, may be made separable from the winding drum. In the latter case, the locking member j is counter-bored, .as shown in dotted lines in Fig. 3, to fit the end of the winding drum 9, and is secured in position by a set screw Z.

Extending beyond the locking member j is a central projection m forming a support for the locking bar 70, the locking bar being formed with a hub 0 encircling the projection. Coiled on the projection on on the outer side of the hub 0, is a spring p, one end of which bears against the hub 0 and the other against a collar 9 fixed on the projection to press the locking bar into operativerelation with the locking member j, to be'engaged by the detents j.

The upper end of the locking bar 71: is movable in an elongatedslot r in the trestle top z', which, with the assistance of the projection m, guides the movement of the looking bar it in a fixed path when withdrawn from engagement with the locking member 7', and during its return thereto.

Attached to the platform support 6 is one end of a winding rope f, the other end of which is coiled on the winding drum 9 in the reverse direction to the suspension rope f. By drawing on the rope f, the drum 9 is caused to revolve in a winding direction, as indicated by arrow in Fig. 4 to wind up the suspension rope and raise the platform 7 support 6, the winding of the rope f on the drum 9 being continued duringthe unwinding of the rope f and the drum 9 being locked at each semi-revolution against unwinding by the engagement of the detents j with the locking bar k.

Connected to the locking bar is are the leads 8, s of the draw rope 8, provided with a handle 8 the leads between the handle and the locking bar passing through suitable pulley blocks t.

lVhen it is desired to unwind the suspension rope f from the winding drum for the lowering of the platform support .9 and platform, the locking bar 70 is disengaged from the detents j by pulling on the draw ropes. hen the draw rope is released, the spring 72 immediately forces the locking bar is back into operative relation with the locking member 3' to be engaged by the detents 7".

The operation of the device may be briefly summarized as follows :For the lowering of the platform support 6, the draw rope is pulled to disengage the locking bar 7s from the detents j. The weight of the platform 2? and the load thereon will then cause the downward movement of the platform support and cause the unwinding of the suspension rope 7 from the drum 9, the unwinding movement of the rope being continued while the locking bar k is disengaged from the detents 79. The unwinding of the suspension rope f from the drum 9 causes the rope to be wound on the drum, and should a stoppage of the platform support 6 occur in the guide ways a, the rope f, owing to its attachment to the platform sup port, will draw the latter downwardly and overcome the stoppage. When the platform support 0 has reached the limit of its downward movement, the draw rope s is released and the spring 7) immediately forces the locking bar it into engagement with the locking member 7' so that the detents y" will engage it and immediately arrest the further unwinding revolution of the winding drum To rewind the suspension rope and raise the platform support 6, the winding rope 7" is unwound from the winding drum 9. During the rewinding of the suspension rope on the winding drum, the detents j successively pass the locking bar 7; which yields suliiciently to allow the detents to clear it as the winding drum and locking member revolve, springing back into position under the influence of the spring 79 to re'engage the detents j immediately they clear it.

The braces u of the trestles a, a are slidably connected to the trestle top 2' by means of brackets ZJ secured to the top of the braces, and bars 10 secured to the trestle top 3y means of the brackets 01 and bars w, the braces u can be folded against the trestles a, a, as shown in dotted lines in Fig. 1, and held in their folded position by means of hooks and eyes at.

The platform t may consist of one plank, or when two planks are used, as shown in Fig. 1, a substantially Ushaped bracket 2 is secured to each of the planks, the ends of which slide through the brackets. In this Way, it is possible to reduced the length of the platform to the length of the longer plank. hen the scaffold is no longer in use, the platform 2 can be reduced to the length of its longer plank and placed inside the trestle and held in that position by means of a chain a being passed across the plank from one side of the trestle to the other. The two trestles can then be placed together and locked in that position by means of hooks d and eyes 6 secured to the braces u.

As shown in Fig. 1, it is necessary to employ two trestles and their related parts, each trestle being similar in all respects to the one above described, and when the sea-ifold is in use, it is possible for the operator, without dismounting from the platform, to adjust it to a higher or lower elevation, and to securely lock it in its adjusted position against descent.

Having thus fully described the nature of my invention, what I claim as new and desire to secure by Letters Patent, is

A scaffold comprising a pair of divergent trestles, winding mechanism at the upper ends thereof, movable supports suspended from the winding mechanism and guided along the divergent trestle legs, and a plat form consisting of extensible platform meinbers, and means for slidably uniting them, the platform members being upheld by the movable supports.

Toronto, February 21st, 1913.

GEORGE ALLEN.

Signed in the presence of EDWARD BnRNs'rEIN,

C. H. Riel-Ins.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patenta, Washington, D C. 

